Humidifying system



y 1939. o. .1. KUENHOLD HUMIDIFYING SYSTEM Filed July 31, 1935 2 Sheets-Sheet 1 3%,MYSW

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y 18, 3 o. J. KUENHOLD 2,166,414 HUMIDIFYING SYSTEM Filed July 51, 1935 2 Sheets-Sheet 2 m a 6 a /v J k 0 llk Patented July 18,1939

PATENT OFFICE HUMIDIFYING SYSTEM Otto J. Kuenhold, Shaker Heights, Ohio, assignor to Monmouth Products Company, Cleveland, Ohio, a corporation of Ohio Application July 31, 1935, Serial No. 34,047

2 Claims. (Cl. 261-104) My invention pertains to a system for adding moisture to the air in rooms and similar spaces and controlling the percentage of humidity maintained therein, said system being adaptable for operation in conjunction with either warm air, hot water or steam heating plants.

The particular advantages of my humidifying system are: the utmost attainablesimplicity of structure, installation and operation; continuous, trouble-free'operation; adaptability of the main operating principles to all types of heating systems; accuracy and convenience of control; constant visible evidence that the system is operating showing how much moisture is being added to the air; automatic downward graduation of the per cent of humidity maintained as weather gets colder and upward graduation as weather gets Warmer so that window condensation will not materially increase as weather gets colder, yet

" the room humidity will be held at highest practicable per cent, regardless of out-door temperature changes. Other advantages will be apparent during the course of the following description.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description'set forth in detail certain mechanism embodying the invention, such disclosed means constitutinghowever, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings:

Fig. 1 is a diagrammatic presentation of my humidifying system including its variations to adapt it to radiator heating systems, or warm air heating systems employing either an evaporating pan as represented in Fig. 1a, or a water spray as represented in Fig. 1b, in the casing of the larnace.

Fig. 2 shows a plan view of the evaporating pan. Fig. 3 shows a vertical longitudinal section through the evaporating pan and a portion of the furnace in which the pan is placed, and taken on line 3-3 of Fig. 2. Fig. 4 shows a vertical transverse section of the evaporating pan on line l-l of Fig. 2. Fig. 5 shows a vertical transverse section on line 55 of Fig. 2. And Fig. 6 is a chart illustrating the principle of operation of my humldifying system.

Referring to Fig. l. The water supply for the humidifying system is taken from any convenient domestic water supply pipe 15, at city pressure,

If a water spray is preferred for introducing by means of tube 85, and is passed successively through a shut-off valve 80, water filter 50 and pressure governor I00. These parts comprise the water supply means and. are fully described in my copending patent application Serial No. 21,576, filed May 15, 1935.

The purpose of the water filter is to remove even microscopic floating particles from the water so that there will be no possibility of clogging at any point and. to make the employment of such tiny valves as are employed in the governor and wall control instrument practical. The pressure governor reduces the water pressure supplied to the system down to minimum requirement for each type of humidifying system, enables accurate automatic humidity control to be attained and serves other important purposes to be described later.

The perfectly clear water at substantially uniform predetermined pressure is supplied by the pressure governor Hill to supply tube I which is extended from the basement upward within a partition wall to the humidity control instrument 200 which is located at convenient height and in an accessible well-lighted location of a central room of the house. After flowing through this control instrument, the water flows through tube 2 down into the basement. From this point tube 2 may be continued as either tube 3, 4' or 5 dependent upon the type of humidifying system that is served by the elements abovedescribed.

If tube 2 is continued as tube 3 it supplies water to an evaporating pan 3!, illustrated in detail by Figs. 2, 3, 4 and 5.

moisture to the circulating air, tube 2 is continued as tube 4 which supplies water to a spray 215 through the automatic intermittent valve 25L If the heating of the rooms is done by steam or hot water radiators, tube 2 is continued as tube 5 which supplies water through the automatic pressure equalizer 35l to main tube 1 from which any number of branches 8 supply water to evaporators 400, mounted in back of each im- 45 portant first floor radiator 298. A branch tube 6 from tube 5 is a main supply tube for the evaporators 4M of all important second floor radiators 299 through branch tubes 9.

The pressure equalizer 35! placed in the main supply tube leading to first floor radiator evaporators gllll is a mercury device which imposes a resistance to the flow of water to first floorradiator evaporators'equal to the average difter- 55 once in hydraulic head between second floor evaporators "I and first floor evaporators 400.

Should any radiator evaporator be supplied with more water than can be evaporated, by reason of that radiator being shut off or for other reasons, the surplus of water will be drained off by drain tubes In and II leading to a main drain tube I2 the outlet II of which drips into a cellar drain. All vertical tubes are preferably placed within partition walls preferably close to the pipes conducting water or steam to and from the radiators. This prevents freezing of the water tubes leading to or from the radiator'evaporators.

In order to comprehend the principles upon which the automatic graduation of the maintained per cent of humidity of my humidifying system is based, certain characteristics of indoor humidified air must be borne in mind. These characteristics, illustrated by the chart Fig. 6 are as follows:

The per cent of air humidity which prevails in a home when no moisture is added and which is hereinafter referred to as the "natural indoor humidity is shown by curve A which assumes 70 degrees indoor temperature.

The per cent of indoor humidity at which window vapor begins to appear, hereinafter called the condensation point? is shown by curve B *ume of water represented by this vertical distance for any given home depends upon the volume of air that leaks into and out of that home.

If sufficient water is evaporated into the air, of a given home, to raise the humidity from the natural humidity, shown by curve A, up to 40 per cent in -35 degree weather, the theoretical per cent of indoor humidity resulting in other weather below about 45 degrees is shown by the dotted line, curve D. It will be noted that the theoretical humidity maintained by this same rate of water evaporation into the indoor air will rise above the window condensation curve B. However, the occurrence of window condensation extracts some moisture from the indoor air and this reduces the actual humidity that is maintained down to curve E.

My system' for automatically graduating the indoor humidity is to simply feed water through the wall control instrument I", Fig. 1 at an accurately maintained rate to the humidifying means, such as the evaporating pan 3", Fig. 1. If the owner adjusts the said control instrument to feed water for evaporation at a rate which results in ust reaching the window' condensation point in 30 degree weather, then the' scale of humidities that will be automatically maintained during colder outdoor temperatures will correspond closely to those/ indicated by curve D. This scale of maintained humidities will slightly increase window condensation in the colder weather but this modifies the extreme indoor air dryness which would occur if the humidity was held below the window condensation point during extremely cold weather. The results obtained by my system of humidity control are therefore ideal.

The foregoing assumes average. wind velocities. Abnormally high or low wind velocity by respectively increasing or decreasing air leakage through the home, will respectively decrease or increase the maintained indoor humidity, but abnormal wind conditions are seldom of more than a few hours duration. The home occupant can correct any wind influence by simply resetting the rate of water feed.

It is essential in my system of humidity control that the evaporating means have adequate evaporative capacity during 30 to 35. degree weather, when the temperature of the furnace or radiators, which determine the rate of evaporation, are of substantially half their maximum temperature.

When the outdoor temperature rises above about 45 degrees the humidity that would be maintained, shown by curve D, rises to a. higher point than is necessary or desirable. To avoid this, I provide means to adjust the evaporative capacity of the evaporators downwardly gt the required extent. In the case of the humi ifying pan 3M, the number of evaporating plates, is reduced and in the case of the radiator evaporators 400 and "I means are provided for reducing the evaporative capacity as will be subsequently explained.

By limiting the maximum evaporative capacity of the evaporating means as above described, the said evaporators will be unable to evaporate all the water supplied by the water feed instrument 200 Fig. 1 in the warmer winter weather and in consequence the per cent of humidity maintained will conform approximately to curve E in the warmer winter weather.

The present almost universally employed method of controlling the maintained indoor humidity is to use a humidostat. These instruments will maintain the per cent of humidity static at whatever per cent the instrument is set. Line C of the chart shows the ensuing results if the humidostat is set to main 45 per cent humidity. It will be noted that as weather gets colder the maintained humidity will be considerably above the window condensation point shown by curve B. The .window condensation occurring increases very rapidly as weather gets colder. The humidostat furthermore causes all water taken from the air by window condensation to be replaced by added evaporation. As a result the window condensation is multiplied to an astonishing extent. The only remedy is to constantly reset the humidostat to comply with weather changes. This serious fault illustrates the great improvement in thestate of the art accomplished by my system of control.

The control of the entire system is accomplished from one central point-the control instNment-mounted upon a wall of a central living room at a conveniently accessible location.

The turning of a .knob is all that is necessary to obtain the maintenance of a per cent of room humidity that will result in no more 'window condensation than the owner desires. The percentage of humidity automatically adjusts itself accordingto changes in outdoor temperature. Referring to Fig. 1, the control knob lit is graduated to show the rate of water feed in, for instance, gallons per day. At 230, the owner can see the water supply dripping through a sealed glass tube. At 240 an indicator shows the existing per cent of room humidity.

crating plates face of both sides is notched at 302 tom middle of the pan contains a series of spaced Referring to Figs. 2, 3, 4 and 5, the operating characteristics of the humidifying Pan will be described:

The pan which is preferably of cast vitreous enamelled metal is indicated at 30L The upper andthe bot-.

apart, upwardly projecting lugs 303 forming notches 304 which are aligned with notches 302 on each side. The above described spaced notches are adapted to receive and hold in vertical parglllltel disposition the porous evaporating plates At the right hand or outer end of the pan, open topped chambers 308 and 308 are formed by walls 3l0, 309 and 301, Fig. 2. Chamber 306 is an inlet chamber to which water is supplied from the control instrument 200 through tube 3. Chamber 300 is an outlet chamber drained bytube l5. Wall 3| 0 is slightly lower than partition wall 301, but wall 303 is-higher than either wall 301 or 3l0. a

When the waterentering the inlet chamber 300 has risen to the level of wall 310, it overflows into the pan which is set level within the casing of the furnace, as shown in Fig. 3, preferably resting on top of the furnace castings" and I1. The outer casing of the furnace is represented by l8, the usually conical bonnet of the casing is indicated at l9 and the usual inverted cone shaped center of the bonnet is shown at 20. The pan is slid in place through a hole cut in the bonnetso that its center line will preferably pass through the vertical center line of the furnace-assuming a cyllndrically shaped furnace. The front flange 320 of the pan remains outside of the casing.

The hole in the bonnet to receive the pan is made I large enough to admit the crating; plates 305 pan with the evapset in place as shown and is closed by a removable plate 2|. -The flange 320 is tapped to receive the tubes 3' and l5..

The pan acts in part asa water reservoir to present water surface to the ,heated and hence dried air circulating throughthe furnace casing into ducts, not shown, leading to the rooms. The

principal functions of the pan'are. however, to support the evaporating plates 305 and to conduct water to the porous evaporating plates. The

evaporating plates 305,.bein'g of porous material,- absorb the water quiterapidly and are therefore continuously in a wet condition. Their wet vertical surfaces, being continuously wiped" by the. heated and hence excessively dry air, rapidly give up water vapor to the circulating air. Capillary action causes the plates 305 to draw water upv from the pan 30l as rapidly as it is evaporated from their surfaces.

The above method of exposing vertical wet sur-.. faces to the generally upwardly moving air increases the evaporative capacity of the pan so that it equals the evaporation which could be obtained from a pan having much greater width, yet the pan can be made so narrow that it offers no appreciable retardance to the air flow.

Another important advantage is that the evapmay be placed centrally as shown in Fig. 3, with reference to the inverted conical top of the furnace wh ch then'acts as a spreader to uniformly distribute the water vapor to all air ducts leading from the furnace. If it is then desired to favor ducts leading frcm'the' front or back of the furnace, the evaporating plates 305 may be moved more toward the front orback accordingly. The pan 30 Lmay also be swung over toward whichever sidev of the furnace is to be plates which projects favored, or a combination of both 'expedients may be employed.

beyond the sides of the pan. The sidewise exten-=- sion is so proportioned withreference tothe height of the plates that all portions will remain substantially of equal wetness. Lime and similar salts contained in the water tend to gravitate toward the bottom and outer ends of the wings 3 I 5 forming excrescences. which may easily be brushed off when the pan is withdrawn from the furnace. v i

The middle bottom portion of the evaporating into the pan is cut in a direction as at 3 to fit the inside of the pan, but from the highest water level 3l3 downwardly, the plate'is cut at an angle as at 3! to form a bottom point as shown. The bottom point enters the recesses 304, Fig. 3. This holds the plates in vertical position.

When the water level descendsto, for instance, level 3", Fig. 5, anly a small cross-sectional area of the porous plate is immersed in the water. The volume of. water which the plates can lift, and hence the wetness of the plates, is dependent partly upon the cross-sectional area that is elmmersed in thewater andpartly upon the average height that 'thewater is lifted. By having the bottomor immersed end of the plate pointed, the amount of water lifted by capillary action and hence the wetness of the plates and the rate at which water is-evaporated, is rapidly decreased at lowered water level and rapidly increased by raised water level.

substantially vertical The above characteristic combined with thefact that the pan' normally holds only about a quart of .water, results in rapid response to increased or decreased rate of water feed to the pan. In general usage, the water level will be at or near minimum in severe winter weather when the furnace isat its hottest and will be at or near maximum inicold weather when the furnace is operated at low capacity.

Should the rate of water feed to the evapcrating pan be greater than the pan and plates can evaporate, as for instance in mild weather, then the water level will'ri'se higher than the top of the wall 3") of the inlet chamber as shown flow water, being fresh, cold water, will not deposit lime in the outlettube l5 as wo be the case if the hot, lime saturated wat mm the pan over-flowed into the outlet t j, Furthermore, the waste of heat due to'permittlng hot water from the pan to overflow, is eliminated.

My method of supplying an accurately measured volume of .water to the evaporating pan greatly reduces chances of overflow. It eliminates float valves or other valves at the pan and so simplifies the structure that no chances for clogging or failure exist. Experience shows that any valve mechanism at the water pan, exposed to heat, moisture and lime deposits cannot be relied upon to remain in operating condition.

An important advantage of the multiple evaporating plate arrangement is the fact that the evaporating capacity can be increased or decreased by merely increasing or d the number oi.plates. In this way, the evaporative capacity can be made just right so that in milder weather, when less evaporation is required, the pan and plates will evaporate less than the amount of delivered to the pan by the control instrument.

Other modes of applyingthe principle of my invention may be employed instead 01' the one explained, change being made as regards the structure herein disclosed. pruflded the means stated by any of the iollowing claims or the equivalent oi such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a humidifying system for a heated space, the combination of control. means for delivering water at a constant rate of flow, means for evaporating water into the air circulated through the space to be heated, a conduit for transmitting water Irom said control means to said evaporating means, said evaporating means comprising a. water receptacle chamber and a plurality of porous plates projecting transversely and upwardl from said chamber, and means in said chamber for diverting the flow of excess water supplied thereto from passing to that portion of said chamber occupied by said plates.

-2. In a humidiiying system, means for evaporating water comprising a reservoir, and a pinrality oi plates composed of water absorbing, porous material, standing on edge and projecting upwardly from said reservoir, the lower portion of said plates being of V-shaped contour, an inlet chamber in said reservoir adapted to overdiow into said reservoir, an outlet chamber adiacent said inlet chamber, a dividing wall separating said chambers from each other, and a second dividing wall separating said chambers from said reservoir, said first-named dividing wall being higher than the overflow levelof said inlet chamber, and said second dividing wall oeing higher than said first-named wall.

O'I'IO J. KUENHOLD. 

